Clutch disc with wavy surfaces

ABSTRACT

A CLUTCH DISC, PARTICULARLY FOR USE ON MOTOR VEHICLES, COMPRISES A CIRCULAR ARRY OF WAVE-SHAPED LEAF SPRINGS FORMED AT THE PERIPHERAL PORTION OF THE SISC ARRANGED BETWEEN AND SECURED TO A PAIR OF OPPOSITELY DIRECTED FRICTION FACING. THE SPRINGS OF TWO DIFFERENT TYPES HAVING, RESPECTIVELY, DIFFERENT AXIAL DEPTHS ALTERNATE IN SUCCESSION AROUND THE DISC AND THEREBY IMPART A WAVE SHAPE TO THE FRICTION FACINGS WHEN THE CLUTCH DISC IS IN AN UNLOADED CONDITION WHEREBY A MULTISTAGE ENGAGEMENT OF THE CLUTCH IS MORE EASILY ACCOMPLISHED.

United States Patent Inventors Appl. No. Filed Patented AssigneesPriority CLUTCH DISC WITH WAVY SURFACES 3 Claims, 5 Drawing Figs.

U.S.Cl 192/107C, 192/106.1 267/165 Int. Cl Fl6d 13/69 Field of Search192/107 [561 References Cited UNITED STATES PATENTS 2,110,051 3/1938Nuttetal 2,195,665 4/1940 Wolfram r 4 2,307,006 12/1942 Wemp 2,337,11112/1943 Joyce r 3,241,644 3/l966 Ridenour Primary Examiner- Benjamin W.Wyche Artorney-Pierce, Scheffler & Parker ABSTRACT: A clutch disc,particularly for use on motor vehil 92/107CP 192/107CP 192/1 07CP192/107CP cles, comprises a circular array of wave-shaped leaf springsformed at the peripheral portion of the disc arranged between I andsecured to a pair of oppositely directed friction facings. The springsof two different types having, respectively, different axial depthsalternate in succession around the disc and thereby impart a wave shapeto thefriction facings when the clutch disc is in an unloaded conditionwhereby a multistage engagement of the clutch'is more easilyaccomplished.

H g N L] n & I -I I Q 7R, 7 ,s i a i I a 29 32A 35 32B 34 PATENTEDJUN2819m SHEET 1 OF 3 FIG. 1

* FIG. 5

, MDOmOP Al BENDING AMOUNT OF LEAF SPRINGS PATENTEU JUN 2 8 l9?! SHEET 2OF 3 1 CLUTCH DISC WITH WAVY SURFACES SUMMARY OF THE INVENTION Thisinvention relates to improvements in clutch discs and more particularlyto clutch discs of the cushion type for use in motor vehicles.

An object of the present invention is to provide a clutch disc in whichthe operation of clutch engagement is improved. More specifically. theinventive idea is to prevent clutch chatter upon starting of the vehicleand to provide a smooth and gradual engagement ofthe driving and drivenmembers.

Another object of this invention is to provide an improved clutch discin which a semiengaged clutch condition that resides between a completeengaged and disengaged clutch condition can be easily obtained, and therush out or break down of the motor vehicles upon starting can beprevented.

Still another object is to provide a clutch disc in which frictionfacings can be prevented from adhering to the flywheel or pressureplate, so that the trailing torque of the facings upon the clutchreleasing is seriously diminished.

A further object of this invention is to provide an improved clutch discin which the amount of the axial movement of the flywheel and thepressure plate can be more decreased than heretofore.

A still further object of this invention includes simplicity ofconstruction and economy in manufacture.

According to the present invention, briefly summarized, there areprovided two kinds of wave shaped leaf springs having respectivelydifferent axial depths which are arranged in alternation around theperiphery of the disc between a pair of annular friction facings so thateach facing has a waved surface when the clutch is released i.e. whenthe clutch disc is in an unloaded condition.

Other objects and the features of the invention will be more clearlyapparent from the following detailed description with respect toexamples of preferred embodiment of the invention when read inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. I is a fragmentary view in side elevation and partly broken awayshowing wave-shaped leaf springs constructed in accordance with thisinvention;

FIG. 2 is a section taken along the plane of line II-II of FIG. I, theclutch being in the engaged position;

FIG. 3 is a sectionalview taken along the plane ofline III-Ill on FIG.1;

FIG. 4 is a perspective view of a portion of the clutch disc, showingespecially the two kinds ofthe leafsprings;

FIG. 5 is a diagram showing a cushioning character of the clutch discaccording to this invention (X) and the conventional one (Y).

DETAILED DESCRIPTION Referring to the drawings, especially FIG. 2thereof, a clutch disc assembly is arranged between a flywheel 11 and apressure plate 12 drivingly mounted on a clutch cover 13. The flywheel11 and the clutch cover 13 are rigidly connected to each other by fixingbolts 14 and rotate with an engine (not shown) through a crank shaft 15rigidly mounted on the flywheel 11 by fixing bolts 16.

The clutch disc 10 comprises a hub 17 having a flange 18 extendingradially outwardly therefrom, the hub 17 having therein a splined bore19 whereby the clutch disc 10 is drivingly mounted on a transmissiondrive shaft 20 and is adapted for sliding movement longitudinallythereon.

At one side of the flange 18, there is provided a disc plate 21 whichextends radially outwardly from the hub 17 to beyond the outer peripheryof the flange 18 as shown in FIG. 2. At the other side of the flange 18,there is provided a side disc plate 22 extending outwardly from the hub17 to adjacent the outer periphery of the flange l8.

LII

There are some torsion dampers 23, four in this embodiment, forproviding a flexible or yieldable driving connection between said discplate 21 and said hub 17. Said dampers 23 made of such materials asrubbers, for example, are seated in openings 24 in the hub flange 18 andalso in openings 25, 26 in the disc plate 21 and sideplate 22,respectively. Both the plate 21 and sideplate 22 are connected to eachother by a plurality of stopper pins 27 which are positioned in recesses28 of said flange 18, thus the disc plate 21 and sideplate 22 are tiedtogether for simultaneous movement, and maintained in parallel spacedrelationship.

At the outer periphery of said disc plate 21, there are connected aplurality of two kinds of lead springs 29 and 30 by means of rivets 31.Each leaf spring is of a generally rectangular shape, and is arrangedalternately in spaced end-to-end order to provide approximatelycontinuous annular cushion means between two facings 32 and 33. Saidfacings 32 and 33, which may be made from any suitable frictionmaterial, are adapted under clutch packing pressure to be packed betweenthe flywheel l1 and the axially shiftable pressure plate 12 of theclutch assembly 10, each facing being provided with apertures 34 for therivets 31 and the other apertures 35 as shown in FIG. 3; On the clutchengaging, the rivets 31 in said apertures 34 will project into theapertures 35. When the pressure plate 12 is released, these frictionfacings 32 and 33 are adapted to assume their normally spacedrelationship with respect to each other.

The axial depth of each one of the leaf springs 29 is greater than thatof the other leaf springs 30 which alternate with springs 29 as shown inFIG. 3; H indicates an axial depth of the spring 29, while H indicatesthe axial depth of the other spring 30. H is greater than H.

It is not necessary to make the leaf springs 29 and 30 with the samespring constant. The spring constants may be the same or different forthe two types of springs.

The crests of the leaf springs 29 and 30 facing axially in one directionare secured by rivets 31 to the facing 32. The other crests thereoffacing axially in the opposite direction; are secured by rivets 31 tothe other facing 33. The difference of the axial depth between thealternating leaf springs 29 and 30 causes the surfaces of the facings 32and 33 to be waved as shown in FIG. 3; The friction surfaces of facings32 and 33 are convexly shaped at 32A and 33A, respectively, while beingconcavely shaped at 32B and 338 respectively.

Upon initial engagement, at first the convex surfaces 32A of the facing32 and the other convex surfaces 33A of the facing 33 engage with theflywheel 11 and pressure plate 12, respectively, thereby transmittingthe engine torque from the crank shaft 15 to the main drive shaft 20through the clutch disc assembly 10; consequently as is clearly shown inFIG. 5 the bending amount A of the leaf springs according to the presentinvention in the semiengaged clutch position C is larger than the amountB of the conventional one, and the rate of the torque change accordingto this invention is smaller than heretofore so that the semiengagedclutch operation can be easily obtained. Then said one concave surfaces328 of the facing 32 and the other concave surfaces 338 of the facing33, too, engage with said flywheel 11 and said pressure plate 12,respectively, thus all the surfaces of facings 32 and 33 are graduallyengaged with the flywheel 11 and pressure plate 12 for multistagefrictional engagement, whereby clutch slipping will be prevented.

These waved surfaces of the facings 32 and 33 prevent the frictionfacings 32 and 33 from adhering to the flywheel 11 or pressure plate 12,so that the trailing torque on the clutch releasing can be eliminated.

Moreover, the higher springs 29 are preloaded by the springs 30 so thatthe axial depth between both facings 29 and 30 is defined and the amountof the axial movement of the flywheel 11 and said pressure plate 12 ismore decreased than heretofore.

It will be apparent without further description that the above-mentionedeffect is achieved not only by the separate depths and alternating insuccession around the disc thereby to impart a wave shape to thefriction facings when said clutch disc is in an unloaded condition.

2. A clutch disc as defined in claim 1 wherein the waveshaped leafsprings of both sets of springs have the same spring constant.

3. A clutch disc as defined in claim 1 wherein the waveshaped leafsprings of one set of springs have a spring constant different from thewave-shaped leaf springs of the other set.

